According to a conventional water resistant structure for an electronic apparatus, packing that wraps one cover on an outer surface of the cover is sandwiched by the outer surface and an inner surface of another cover that faces the outer surface (see, e.g., Japanese Laid-Open Patent Publication No. 2006-33202). According to another water resistant structure, an O-ring attached to an outer surface of a protrusion protruding from a back surface of a lid covering an opening is caused to be in contact with an inner surface of the opening (see, e.g., Japanese Laid-Open Patent Publication No. 2009-111720).
Nonetheless, since the shape and the appearance of the lid differ according to the model of the electronic apparatus, a problem arises in that a mold needs to be newly produced for each model even when the back surface of the lid such as a protrusion has the same shape for each of the models. When an O-ring is attached to the outer surface of the protrusion, the O-ring tends to be twisted and the O-ring needs to be reattached. Therefore, the first time quality may drop.